SU943610A1 - Method of localizing cable damage - Google Patents

Description

(5t) METHOD FOR DETERMINING THE PLACE OF DAMAGE TO THE CABLE

one.

The invention relates to electrical measuring equipment and can be used to create devices for troubleshooting in power cable lines.

A known method for determining the place of closure of a conductor on a metal sheath of a multicore power cable is based on applying a test voltage of increased frequency between damaged conductors, connecting an intact conductor with a metal sheath at the opposite end of the cable and applying an additional test voltage is between a damaged conductor and a metal cable sheath is opposed to the main test voltage, regulation of the current of one of the voltages and determining the location of the circuit 20 by measuring eniyu EMF on the track cables Ul.

The disadvantages of this method are low accuracy and low efficiency due to the need to carry out preliminary adjustments.

The closest to the present invention is a method for determining the cable damage location, including the supply of a test voltage of a first frequency between a common bus and a serviceable core cable, which is connected to a common bus at the other end, the inclusion of a test voltage of a second frequency between damaged cable cores, sensor movement along the cable and recording signals of test voltages of two frequencies C2.

The disadvantages of this method are also low accuracy and efficiency in determining the location of damage.

The purpose of the invention is to improve the accuracy and efficiency of determining the location of damage to the cable.

Claims (2)

In order to achieve this goal, in a known method for determining cable damage location 39, including the supply of a test voltage of a first frequency between a common bus and a functioning residential cable, which is connected to a common bus at the other end, switching on a test voltage of a second frequency between damaged cable cores, moving the sensor along the cable and recording the signals of test voltages of two frequencies, the test voltage of the second frequency modulates the test voltage of the first frequency, and the received voltage is modulated This signal is demodulated and the phase shift between the modulation frequency and the received test voltage of the second frequency is distinguished, and the cable damage point is judged by an abrupt change in the phase shift. The drawing shows a block diagram of a device implementing measurements in this method. The device comprises a test voltage generator 1 of the first frequency connected between a common bus and an intact residential cable 2 connected to a common bus at the other end, a generator of the second frequency test voltage connected to the damaged conductors of the cable 2 and to the modulation inputs of the generator 1, sensor 4, band-pass filter 5 of the test voltage of the first frequency, band-pass filter 6 of the test voltage of the second frequency, indicator 7 of the test voltage of the first frequency, demodulator 8, meter 9 of the phase. and a phase shift indicator 10. The process of determining the location of damage to the cable is as follows. The frequency of generator 1 is modulated by the signal of generator 3. On the route, the signals from generators 1 and 3 are received using sensor C. The band-pass filter 5 selects the signal of generator 1, which is detected by indicator 7. filter 6 extracts the signal from oscillator 3, which is detected in demodulator 8, as a result of which a modulating signal from oscillator 3 is output from demodulator 8. In phase shift meter 9, the phase shift of the signal r is determined. Generator 3 received on the track relative to the reference signal of the same generator obtained from the demodulator 8. The generator current 3 behind the fault site is created by the capacitance of the damaged cable parts behind the fault site, as well as by the spreading currents for the case of single-phase closure. Thus, its phase behind the site of damage changes dramatically, which is recorded by the phase shift indicator 10. In this method, higher accuracy is achieved through the use of a phase method of damage fixation, which ensures a higher sensitivity of the devices. Search efficiency is achieved by reducing the time for preliminary adjustments and searching for the maximum signal. Claim method for locating cable damage, including supplying a test voltage of a first frequency, between a common bus and a healthy cable, which is connected to a common bus at the other end, switching on a second frequency test voltage between damaged cable cores, moving the sensor along the cable and recording signals of test voltages of two frequencies, characterized in that, in order to increase the languor and efficiency of determining the location of damage to the cable, the test voltage of the second The frequencies modulate the test voltage of the first frequency, and the received modulated signal demodulates and separates the phase shift between the modulation frequency and the received test voltage of the second frequency, and the location of the cable damage is judged by a step change in the phase shift. Sources of information taken into account in the examination 1. USSR author's certificate number 476524, cl. G 01 R 31/08, 1974. 2. USSR author's certificate number 554510, cl. G G1R 31/08, 1978. / h / h t /